Output stability or drift over time leading to measurement inaccuracies has long been a major deficiency for gas sensors irrespective of what technology or methodology is used for their conception or realization. Output software correction may alleviate the problem somewhat but it is in many instances inaccurate and not even always applicable. It has long been the objective of many researchers in this field to overcome this problem fundamentally and for good. Recently the present inventor in U.S. application Ser. No. 12/859,749 advanced the teaching of an Absorption Biased NDIR Gas Sensing Methodology which is capable of eliminating substantially all NDIR gas sensor output drifts over time without the need for re-calibration (Wong, filed 19-AUG-2010). As it turns out, the solution to solving this output drift problem for gas sensors actually lies deeper than the availability of superior NDIR gas sensor types even though they can indeed be designed to be capable of maintaining measurement accuracy over time. The fact of the matter is that people have experienced gas sensor output instability for such a long time in the past that when output stable sensors really come along nobody would believe it. Until such time that stable gas sensors become widely available and users begin to consider their performance as trustworthy and truly believable, the real need today must be viewed at a completely different perspective and that is to be able to come up with a fast, inexpensive and simple methodology that can easily check the accuracy of gas sensors and more importantly, just as easy and simple, hence inexpensive, to re-calibrate them when they are found to be inaccurate.
It is therefore the primary objective of the present invention for the present author to advance a novel methodology to simply and easily re-calibrate an NDIR gas sensor.